Magnetic field effects on Ni-Fe alloys codeposition

The codeposition behaviour of nickel-iron alloys has been studied in acid sulphate electrolytes in the presence of a magnetic field superimposed parallel to the surface. The magneto-induced modifications in the Ni-Fe film composition and morphology were attributed to an increase of the surface concentration of inhibiting species (i.e. Fe-II) by magnetohydrodynamic effects. In addition, the X-ray mapping demonstrates a high homogeneity of the distribution of nickel and iron atoms throughout the surface under the magnetic convection, except in the vicinity of hydrogen bubbles, where can be observed a disturbance of the distribution of nickel and iron atoms. It was also demonstrated that the magnetic field slightly affects the surface magnetic properties. The results of the electrochemical investigation reveal the same inhibition phenomenon that leads to reduce the current density and increase the adsorption-loop amplitude of the Nyquist electrochemical impedance diagrams. (C) 2004 Elsevier B.V. All rights reserved.